Our previous research identified specific cognitive, psychomotor, and sensory-perceptual deficits in young, mild, and untreated hypertensive subjects. It was subsequently show on follow-up after treatment that these behavioral deficits were substantially reduced in those patients who had received effective pharmacological treatment but were not reversed in untreated patients. The data from these studies suggests that, among other effects of high blood pressure, there may be a shift in hemispheric intercommunication or lateralization. The present proposal is designed to test lateralized behavioral functions in a young group of newly identified and untreated hypertensives and in an older group of hypertensive males who have been undergoing antihypertensive therapy for at least five years. Normotensive controls, matched in age, race and educational levels, will provide the appropriate comparison groups. In addition to the neuropsychological assessment of laterality, the experiments will test the nonverbal sensitivity of the hypertensive vs. normotensive subjects. It is hypothesized that elevated blood pressure affects the CNS, particularly in its right hemisphere functions, so that the perception and expression of expressive social cues are impaired. Subjects will be studied in three social situations designed to measure their capacity to detect and respond appropriately to the subtle cues of facial expression, paralinguistic behaviors, etc. Physiological measures will be obtained during one of the tasks. It is hypothesized that the evidence from the laterality tests and the nonverbal communication tests, in combination, will provide strong evidence that the so-called "hypertensive personality" is, in fact, a result of chronic high blood pressure rather than an etiologic factor. The detrimental effects of hypertension on cortical function may disrupt the patient's ability to perceive and respond to the subtle, dynamic configurational cues which convey the important modifiers and affect in interpersonal interactions.